This invention relates to comminution devices or pulverizing machines which use rotors and stators located within a housing to pulverize certain materials. Such machines usually have a pulverant inlet means, a pulverant outlet means utilizing the rotor members to impart velocity to the pulverant material so that impact on the stator members reduces the particle size of the pulverant material.
In such machines, wear on the stators and rotors is an extreme problem and the use of a hard wear resistant material, such as a cemented hard metal carbide material, is desirable. Such material has found use in certain types of comminution machines; see, for example, U.S. Pat. No. 3,995,782, granted to applicants' corporation.
Early pulverizing blade assemblies have been made comprising a hard cemented metal carbide blade and a plug member. The blade, however, was butt welded to one end of the member. The plug member was then threadedly held in the housing of a pulverizing device so that the stator blades extended so as to cooperate with the rotors in pulverizing material.
The problem in such early brazed cemented hard metal carbide pulverizing blade assemblies was that frequent failures occurred due to the residual brazing stresses in the blade. The residual brazing stresses, combined with the impact loading from the material being worked in the machine, could cause premature failure of at least one of the cemented hard metal carbide blades. The failure of one blade was usually enough to cause failure of many more blades within the machine.